The term 'heart disease' covers a multitude of heart conditions, some more serious than others. Heart disease is the biggest killer of men and women in the West accounting for over 25% of deaths. This entry deals specifically with angina and in part with heart attack.
Coronary Heart Disease
This is a disease of the main arteries of the heart. These diseased arteries lead to a condition called Angina Pectoris commonly called 'angina'. The condition can also lead to a heart attack (mycardial infarction).
There is a misconception that the heart gets its oxygen from the blood within the heart itself when in actual fact it gets the oxygen from blood flow to the heart from coronary arteries, known as coronary circulation. Problems occur when the heart's energy requirements exceed the ability of the blood flow to supply them.
There are two types of angina: 'stable angina' which is usually controlled with medication, diet and certain exercises and 'unstable angina'. Unstable angina is potentially dangerous as this has the potential to go on to become a full-blown heart attack (mycardial infarction). Angina becomes unstable when the main arteries are virtually blocked allowing very little blood flow to the heart and chest pain occurs when you are at rest either sitting or lying down.
Cardio-vascular disease affects arteries throughout the body and usually refers to the furring up of arteries resulting in restricted blood flow. It commonly affects the legs as well.
The most common cause of narrowing of the arteries to the heart are excess fatty deposits (known as 'atheroma') which is a result of high cholesterol.
Other major contributory factors are:
- Poor diet
- High Blood Pressure
- Lack of Exercise
- Those with a family history of heart disease
High cholesterol is usually a result of a high fat diet but can also be an over-functioning liver producing too much Low Density Lipoprotein (LDL) cholesterol.
There are two types of cholesterol known as LDL (Low Density Lipoprotein) and HDL (High Density Lipoprotein). The LDL cholesterol carries cholesterol from the liver to the body's cells and if supply exceeds demand this can lead to a harmful build up of atheroma, the fatty deposits left in the arteries.
HDL cholesterol takes cholesterol away from the body's cells back to the liver where it is either broken down or excreted.
You can find out more about cholestrol at the BBC's Health/heart conditions website.
Obesity is an obvious candidate that leads to heart disease. Diabetes is also another but it's also not unusual for someone to get heart disease first and then go on to develop diabetes. It is also a fact that depending on the severity of the heart disease a patient can become obese as a result of not being able to exercise properly hence the need for a good sensible diet.
Additional information on diabetes, exercise, blood pressure and diet can be found at:
Unfortunately it is often the case that the first time anyone realises they have a problem is when they actually have a heart attack. After surviving a heart attack, tests will be carried out to determine the cause.
Others may be fortunate and get warnings beforehand. The initial symptoms are:
A pain or tightness in the centre of the chest that can radiate into the arms, neck, jaw or back.
Breathlessness is not uncommon.
If you suffer any of the above symptoms seek medical advice as soon as possible.
An initial diagnosis can be made by having an ECG, (Electrocardiograph). This simply involves having a series of electrodes attached to the chest and lower legs. The electrodes pick up the electrical impulses from heart activity and from blood flow which then produces a printout showing the trace patterns. A normal trace pattern shows in the form of a graph with even peaks and troughs showing different impulses produced at each stage of the cardiac cycle. Any abnormalities can be seen fairly quickly by the doctor and further tests and treatment then arranged.
More on the cardiac cycle can be found at A898671.
If an actual heart attack is suspected, as well as showing up on the ECG, blood tests are taken which measure certain enzymes that are released by the heart muscle during an attack. These are Troponin I and Troponin T tests. There should be little or no Troponin in the blood if there is no damage to the heart muscle itself. Troponin is released into the blood stream and is measured up to six hours after the initial onset of the attack.
Once an initial diagnosis is made there are further tests that can be carried out to ascertain the extent of the problem.
The most common is an angiogram. This is normally done as a day patient and involves a tube being inserted into the main artery in the groin through which a fine wire/tube is fed up the artery to the heart. A dye is injected and this allows the arteries to show up clearly on a video/x-ray. The resulting pictures will show the cardiologist where and how severe the blockage is and will then lead on to whether a full by-pass operation is required or a procedure known as angioplasty with a stent (more on this in 'Treatments' section below).
An exercise stress test can also be carried out. This involves the patient being wired to a heart monitoring machine and a blood pressure monitor and then the patient starts by walking on a treadmill. The treadmill is adjusted for different levels of severity mimicking walking uphill and possibly jogging. The test can last for up to 20 minutes after which the printed results are studied to see what abnormalities, if any, are present. This test is carried out with qualified staff present in case it triggers an angina attack or worse!
For patients unable to have either an angiogram or carry out a stress test then there is a sonar test where an ultra-sound scanner is used and a drug injected to make the heart work harder. This is especially usefull for seeing the operation of the heart valves as well. This test can also be carried out without the need for the heart to be put under stress with drugs.
The angiogram is the only test that involves what medics term invasive diagnostics with more risk. All three of the above procedures are relatively safe and routine these days but always bear in mind that there will be a degree of risk in all medical tests.
There are many different drugs for treating heart disease and there are more either under review or in use under supervision in hospitals. Although there are many drugs they all belong to a few main types/categories. Most heart drugs change how the heart or circulation works. Drugs can be used to treat:
- Heart attack
- High blood pressure
- Disorders of heart rhythms
- Heart failure
Some drugs can be used to treat more than one condition. Others are used to prevent coronary heart disease.
Angina - The main drugs used to prevent or treat angina are beta-blockers, calcium blockers, nitrates and potassium channel activators.
Heart Attack - Also known as myocardial infarction or coronary thrombosis. It is not possible within this entry to delve too deeply into this one as the drugs used are generally given at hospital and not self administered. Aspirin is used to reduce the risk of blood clots, and hospitals will administer clot busting enzymes called thrombolytics.
High Blood Pressure - A wide range of drugs are used including ACE inhibitors, beta blockers, calcium channel blockers and diuretics.
Prevention of Heart Disease - Drugs used for this include cholesterol lowering drugs known as statins, also drugs to lower high blood pressure and to prevent blood clotting.
More information on the drugs in use and what's likely to be available can be found at British Heart Foundation.
Medicines and How They Work
Beta-blockers (e.g. Atenonol) - These block the actions of hormones such as adrenaline that make the heart beat harder and faster. They are very effective in preventing angina but work too slowly in relieving chest pain from an angina attack. They are also very effective in lowering blood pressure therefore reducing the risk of further heart attacks. Some types of beta-blockers can help control abnormal heart rhythms and heart failure.
Calcium Channel Blockers (e.g. Amlodopine) - These drugs reduce the amount of calcium entering the muscle cells of the arteries causing them to relax and widen resulting in a better blood flow to the heart and reducing the work the heart has to do. Calcium Channel Blockers are sometimes used to treat angina often together with other drugs. They are also used to reduce high blood pressure.
Nitrates (e.g. Isosorbide Mononitrate) - Nitrates relax the muscles in the walls of arteries including the coronary arteries and make them wider. They are very useful in relieving angina pain and in preventing predictable attacks for example, prior to physical exertion. Isosorbide mononitrate is a slow release nitrate that works over a period of time but does not give immediate relief from angina pain. Glyceryl Trinitrate tablets or GTN spray is the normal method of relieving angina pain. The tablet is placed under the tongue and dissolves quickly. You do not swallow them as this makes them ineffective. The GTN spray is sprayed under the tongue also.
Potassium Channel Activators (e.g. Nicorandil)- These have a similar effect to nitrates as they relax the walls of the arteries and so improve blood flow to the heart. Unlike Nitrates they do not appear to become less effective with continued use.
Statins (e.g. Atorvastatin) - Blood Lipids is the name given to the fatty deposits in the blood including HDL and LDL Cholesterol. Statins are very effective in reducing these levels which if left lead to the furring up of the arteries. These are used if lifestyle and diet changes do not lower the cholesterol naturally.
Aspirin/Anti-Platelet/Anti-Coagulents - These are used to prevent blood clotting and reduces stickiness of blood platelets. A new drug called Clopidrogel is also now in use in conjunction with aspirin. You have to be aware of bleeding whilst on anti-coagulent drugs because they stop blood clotting which means you can bleed for longer.
Warfarin - This is an anti-coagulent that is in common use but has to be monitored with regular blood tests. There are replacement medicines being developed, Clopidrogel for one that does the same job without the need for monitoring in the form of regular blood tests.
Angioplasty with Stents - This procedure takes the same form as the diagnostic test, the angiogram. On the end of the tube inserted into the main artery, usually in the groin, is a tiny balloon that is placed in the restricted part of the artery and inflated. This opens the artery up thus allowing free flow of blood. A stent (a very fine wire gauze tube) is also inserted to keep the artery open. More than one stent can be used. This procedure normally reqires an overnight stay in hospital.
Coronary Artery By-Pass Surgery - This is major surgery and is done as a last resort. It involves the opening of the chest cavity and transplanting veins, usually taken from the legs and from the chest wall and grafted onto the heart to by-pass severe blockages. It requires the heart to be stopped and cooled which reduces its oxygen requirement by over 95%. This prevents any tissue damage whilst the blood supply is interupted. Circulation is maintained by an electric heart/lung machine. The operation can take up to six hours if there are no complications. This requires a minimum stay in hospital of at least a week.